After Doom of Valyria, a century of violence and turmoil engulfed Essos. Volantis, the strongest of the 9 daughters claimed herself to be the successor of the Valyrian Empire and sought to subjugate her sisters by force to revive Valyria.
While initially successful, they were soon facing an alliance of all the Free cities (Except Lorath), Stormlands and Targaryens of Dragonstone (Who joined the war on request of Pentos and Tyrosh).
I can understand the reasons of all the other belligerents.
- Free cities wanted to remain free of Volantene yoke.
- Stormlanders were threatened by Volantis' aggressive expansion right across their shores.
But what about the Targaryens? Why would they feel threatened by Volantis or a revival of Valyria 2.0 (sans Dragons) when they had the only dragons in the world? Of course Dragonstone was part of the Valyrian freehold and Volantis may have laid claim to it as successor to Valyria but three dragons would have been more than enough to repel any invasion from the East. Even if Valyria was revived, the Targaryens could have actually forced the new Empire to accept their leadership as the last Dragonlords and the last of the 40 Freeholder families. Not to mention, there'd be a significant part of the population who'd support the Targaryens precisely because of that. But still we see Aegon completely against the idea of the Valyrian resurgence. Not just that, even his heirs were absolutely opposed to a Valyrian revival. I talked about those reasons in some of my previous answers but they just don't convince me entirely for reasons outlined above.
Did Pentos and Tyrosh promise some lucrative deal to the young Lord of Dragonstone to get the Targaryens on their side?
Why did Aegon the Conqueror ally himself with the Free cities when he never showed interest in Eastern politics before or after that war?